This disclosure relates in general to networks and, but not by way of limitation, to packet switched networks using a domain name service.
Locating the Internet user within a network can be helpful for many reasons. Ad serving services sometimes use location information to choose location-specific ads. Content providers and content delivery networks (CDNs) sometimes use location information in routing of content to the Internet user in an efficient manner.
There are algorithms to determine a location of an Internet user based upon the location of the client local domain name service (DNS) server, sometimes also called a DNS proxy server, that the user's device utilizes to resolve domain names into IP addresses. Alternatively, routing protocols can route DNS resolution requests from the client local DNS server to a close authoritative name server for a particular domain name and a specific server IP address can then be assigned on the basis of that routing result. A presumption is made in these and similar processes, namely, that the location of the user's client local DNS server is in close network proximity to the Internet location of the user. Unfortunately, some report that 5-10% of Internet users are not located in close network proximity to their DNS server.
Internet users get Internet service through an access network or Internet service provider (ISP). The device of the user requests content objects from the Internet by using a host name and/or a domain name, along with a path and file name. Taken together, this is commonly referred to as a universal resource locator (URL). A domain name service (DNS) is used to convert the host name and/or the domain name into one or more Internet protocol (IP) addresses through a process called domain name resolution. Once the device receives the name resolution, containing server IP address(es), the content object is requested from a server as indicated by the IP address(es).
The access network typically provides a client local DNS server that allows resolving the domain name in a recursive process. The client local DNS server acts as a proxy to the Internet user's device and gathers the correct IP address(es) from other DNS servers before returning the address(es) to the Internet user. In some cases, the client local name DNS server may return a cached IP address that was previously found in a recursive manner. These and other DNS servers together form the Internet DNS system that allows resolving every valid domain and/or host into an IP address. The client local name DNS server normally includes function that enables it to track and adhere to a time-to-live for each returned IP address. The time-to-live is normally, but not always, specified by the authoritative DNS server for the domain name. After expiration of the time-to-live, the cached IP address(es) should no longer be used.
There are public DNS servers on the Internet away from the user's access network that cooperate as a DNS system. These public DNS servers provide recursive IP address look-up in much the same way as a client local DNS server within the access network. Unless access is blocked by an enterprise network or access network, Internet users can effectively use public DNS servers. For networks that block DNS requests destined for more than a few approved IP addresses, users must use the approved IP addresses for their DNS requests. Typically, the approved IP addresses are those within the access or enterprise network or those specifically approved by the access or enterprise network.
There are authoritative DNS servers on the Internet that are the final provider of IP addresses for a given Internet domain name. Through the recursive process, a DNS server, such as a client local DNS server, ultimately ends up communicating with an authoritative DNS server to accurately resolve the host name and/or domain name into IP address(es). Authoritative DNS servers for domains can be maintained by content originators, a CDN servicing the content originator, an ISP, a DNS services provider, or another organization.
A user device may automatically communicate with client local DNS servers provided by the ISP, access network, or enterprise network utilizing a protocol such as the Distributed Host Command Protocol (DHCP) or similar protocols. Through one or more successive DHCP transactions, client local DNS server IP addresses provided by the access server are communicated to a DNS resolver subsystem of the user device. Often, there are primary and secondary client local DNS server IP addresses provided, so that if the primary client local DNS server is not available (failed, powered off, not reachable via the network, etc.), the secondary client local name server can be used in the alternative. The DHCP or similar process is often performed by the computer operating system or firmware in an Internet connected device.
In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.